Executive Summary - Department of Invertebrate Zoology

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were then processed as follows . After weighing the "mini-corer" the
sediment sample was extruded into 90 ml of sterile sea water irn a
Waring blender and homogenized for one minute . One ml volumes of this
homogenate (1 :10 dilution of sediment v/v) were diluted by appropriate
powers of ten and used to inocslate media for enumeration of
hetero .*.rophic and petroleum-degrading marine bacteria .
Histop t hology
(jrganisms Chosen for Analysis . Twelve benthic marine
invertebrates were ci.osen for histopathological analysis from SBT,
anchor dredge, or ottec trawl catch :
Molluscs : Astarte undata , A . castanea , and Placoep
cten mabellanicus
Shrimp : Dichelopandalus leptocerus , Pontophilus
brevirostr ls, and Cran on septemspinosa
Crabs : Cancer irroratus and C . borealis
Echinoderms : Echinarachnius 21rma, Asterias forbesi ,
A . vulgaris and Astropecten Emericanus .
Organs and Tissues Samled . For routine work, the smaller
crustacea, specifically the shrimp and small crabs, were fixed whole
without any attempt to dissect out discrete organ systems . The
echinoderms and small molluscs were dissected to yield only broad
anatomical units such as the arms or disk area in the echinoderm or
portions of gut, mantle, and foot in the smaller molluscs . The larger
crabs and the giant scallop, P . magellanicus, were dissected to
provtde portions of gill, digestive diverticula, stomach (crabs only),
s)nad, muscle, heart, mantle (scallops only), or kidney (scallops
only) . Fine dissections of other animals were occasionally performed
when it was desired to obtain material for plastic embedding .
Fixation . Samplss to be processed in the "routine" manner were
preserved in Dietrich's fluid . Although Dietrich's fixative was an
adequate histological fixative, it did not preserve the fine
structural elements of tissues and appeared to wash out glycogen from
tissues . In order to appreciate the finer morphological details,
selected portions of the animalb referred to above were preserved in
aqueous phobphate-buffered, acrolein-formaldehyde mixture (PAF) .
Small portions of tissue, generally less than 5 mn in diameter, were
placed in PAF, transported back to the laboratory and embedded in
glycol methacrylate for routine examination at the light microscope
level .
Community Str ucture and Food Habits of Fishes
Sampling :or demersal fishes consisted of 15-minute tows with a
45 ft . (13 .7 m) headrope, lined, semi-balloon trawl . Six stations,
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